Merge pull request #6693 from mpg/optimize-with-asan-2.28

[backport 2.28] Optimize with asan
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 992e3b3..ba37e33 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -185,7 +185,8 @@
     export CTEST_OUTPUT_ON_FAILURE=1
 
     # CFLAGS and LDFLAGS for Asan builds that don't use CMake
-    ASAN_CFLAGS='-Werror -Wall -Wextra -fsanitize=address,undefined -fno-sanitize-recover=all'
+    # default to -O2, use -Ox _after_ this if you want another level
+    ASAN_CFLAGS='-O2 -Werror -fsanitize=address,undefined -fno-sanitize-recover=all'
 
     # Gather the list of available components. These are the functions
     # defined in this script whose name starts with "component_".